Heat sink



FIG. 1 is a front elevational view of a heat sink showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a bottom, rear and left side perspective view thereof; and,

FIG. 8 is a bottom, front and right side perspective view showing the heat sink in an unfolded state.

The broken lines in the drawings illustrate portions of the heat sink which form no part of the claimed design. 

CLAIM The ornamental design for a heat sink, as shown and described. 